/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2008-2011, Salzburg Research. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * - Neither the name of the KiWi Project nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Contributor(s):
 * sschaffe
 *
 * File Info:
 * User: sschaffe
 * Date: 2011/01/27
 * Time: 15:19
 *
 * Project: KiWi2, kiwi-core module
 */

package kiwi.core.services.io;

import kiwi.core.api.io.KiWiSerializer;
import kiwi.core.api.sesame.KiWiSesameService;
import kiwi.core.model.rdf.KiWiTriple;
import org.openrdf.repository.Repository;
import org.openrdf.repository.RepositoryConnection;
import org.openrdf.repository.RepositoryException;
import org.openrdf.repository.sail.SailRepository;
import org.openrdf.rio.RDFFormat;
import org.openrdf.rio.RDFHandler;
import org.openrdf.rio.RDFHandlerException;
import org.openrdf.rio.n3.N3Writer;
import org.openrdf.rio.ntriples.NTriplesWriter;
import org.openrdf.rio.rdfxml.util.RDFXMLPrettyWriter;
import org.openrdf.rio.trig.TriGWriter;
import org.openrdf.rio.trix.TriXWriter;
import org.openrdf.rio.turtle.TurtleWriter;
import org.openrdf.sail.memory.MemoryStore;
import org.slf4j.Logger;

import javax.inject.Inject;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;

/**
 * Add file description here!
 * <p/>
 * User: sschaffe
 */
public abstract class GenericSesameSerializer implements KiWiSerializer {

    @Inject
    private Logger log;


    @Inject
    private KiWiSesameService sesameService;


    private RDFFormat format;


    public GenericSesameSerializer() {
        this.format = RDFFormat.RDFXML;
    }


    protected GenericSesameSerializer(RDFFormat format) {
         this.format = format;
    }


    /**
     * Serialize a collection of triples using the serializer and return the result as a string that can be used for
     * further processing.
     *
     * @param triples an iterable containing the triples to be serialized
     * @return
     * @throws java.io.IOException
     */
    @Override
    public String serializeTriples(Iterable<KiWiTriple> triples) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();

        try {
            serializeTriples(triples,out);

            return new String(out.toByteArray(), "utf-8");
        } catch (IOException ex) {
            log.error("I/O exception while serialising to string; should never happen!");
            return "";
        }
    }

    /**
     * Serialize a collection of triples using the serializer and write them to the OutputStream given as argument.
     * May be used for more memory-efficient serialisation of big collections of triples.
     *
     * @param triples an iterable containing the triples to be serialized
     * @param out
     * @throws java.io.IOException
     */
    @Override
    public void serializeTriples(Iterable<KiWiTriple> triples, OutputStream out) throws IOException {


        RDFHandler handler;

        if(RDFFormat.RDFXML == format) {
            handler = new RDFXMLPrettyWriter(out);
        } else if(RDFFormat.N3 == format) {
            handler = new N3Writer(out);
        } else if(RDFFormat.TURTLE == format) {
            handler = new TurtleWriter(out);
        } else if(RDFFormat.NTRIPLES == format) {
            handler = new NTriplesWriter(out);
        } else if(RDFFormat.TRIG == format) {
            handler = new TriGWriter(out);
        } else if(RDFFormat.TRIX == format) {
            handler = new TriXWriter(out);
        } else {
            handler = new RDFXMLPrettyWriter(out);
        }

        Repository repository = new SailRepository(new MemoryStore());
        try {
			repository.initialize();

            sesameService.exportToSesame(triples,repository);

            RepositoryConnection con = repository.getConnection();

            con.export(handler);

            con.close();

            repository.shutDown();
        } catch (RepositoryException e) {
            log.error("repository exception while reading triples into temporary sesame repository",e);
        } catch (RDFHandlerException e) {
            log.error("RDF handler raised an error while serialising RDF data",e);
        }

    }

    /**
     * Serialize a collection of triples using the serializer and write them to the Writer given as argument.
     * May be used for more memory-efficient serialisation of big collections of triples.
     *
     * @param triples an iterable containing the triples to be serialized
     * @param writer
     * @throws java.io.IOException
     */
    @Override
    public void serializeTriples(Iterable<KiWiTriple> triples, Writer writer) throws IOException {


        RDFHandler handler;

        if(RDFFormat.RDFXML == format) {
            handler = new RDFXMLPrettyWriter(writer);
        } else if(RDFFormat.N3 == format) {
            handler = new N3Writer(writer);
        } else if(RDFFormat.TURTLE == format) {
            handler = new TurtleWriter(writer);
        } else if(RDFFormat.NTRIPLES == format) {
            handler = new NTriplesWriter(writer);
        } else if(RDFFormat.TRIG == format) {
            handler = new TriGWriter(writer);
        } else if(RDFFormat.TRIX == format) {
            handler = new TriXWriter(writer);
        } else {
            handler = new RDFXMLPrettyWriter(writer);
        }

        Repository repository = new SailRepository(new MemoryStore());
        try {
			repository.initialize();

            sesameService.exportToSesame(triples,repository);

            RepositoryConnection con = repository.getConnection();

            con.export(handler);

            con.close();

            repository.shutDown();
        } catch (RepositoryException e) {
            log.error("repository exception while reading triples into temporary sesame repository",e);
        } catch (RDFHandlerException e) {
            log.error("RDF/XML handler raised an error while serialising RDF data",e);
        }
    }
}
